1000 calories of radiant heat is incident on a body. If the body absorbs 400 calories of heat, find the coefficient of emission of the body.

Answer

To solve the problem of finding the coefficient of emission of a body that absorbs a certain amount of radiant heat, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Given Values:**
- Total radiant heat incident on the body (Q_incident) = 1000 calories
- Heat absorbed by the body (Q_absorbed) = 400 calories

2. **Understanding the Coefficient of Emission:**
- The coefficient of emission (e) is defined as the ratio of the heat absorbed by the body to the heat incident on it.
- Mathematically, this can be expressed as:
\[ e = \frac{Q_{\text{absorbed}}}{Q_{\text{incident}}} \]

3. **Substituting the Values:**
- Now, substitute the given values into the formula:
\[ e = \frac{400 \text{ calories}}{1000 \text{ calories}} \]

4. **Calculating the Coefficient:**
- Simplifying the fraction:
\[ e = \frac{400}{1000} = 0.4 \]

5. **Conclusion:**
- The coefficient of emission of the body is 0.4. Since it is a coefficient, it is dimensionless and does not have any units.

### Final Answer:
The coefficient of emission of the body is **0.4**.